Co-pending international patent application PCT/GB00/00175 (published WO 00/44093) has the same inventor as this application, and relates to such electronic signal production. Suitable disclosed electronic circuitry includes composite electromagnetic/semiconductor structures for providing timing signals in integrated circuits (ICs), typically in clocking digital ICs, including VLSI (very large scale integrated) circuits. Uniquely such provisions have no physical distinction between signal operation means and signal distribution means, those functions now being merged in the same physical means.
Structurally, suitable such means includes at least one signal path exhibiting endless electromagnetic continuity and affording signal phase inversion of an electromagnetic wave type signal, and path-associated active means. Functionally, preferred electromagnetic travelling wave recirculation of such endlessly electromagnetically continuous path can produce pulses with a repetition rate having a time constant related to and effectively defined by the electrical length of said signal path. Such endless signal paths are inherently unterminated so free of termination and reflection problems, and low impedance is not a problem as only “top-up” energy is required to maintain amplitude of pulse waveforms. Fast switching said path-associated active means is advantageous to direct production of highly square wave forms, with rise and fall times according to switching between voltage levels and spacings thus pulse durations according to transit of said signal path.
Such operation can be viewed as effectively repeating traversal of said signal path by a voltage level transition that can be very fast, the transition being effectively inverted by its said signal path traversal. Suitable said signal path can be of transmission line nature, as realisable for ICs on an on-chip basis by such as microstrip, coplanar waveguide or stripline lithography using resist patterns and etching. Functional signal path implementation can be as substantially parallel double-loops with insulated cross-over formation, traceable as a substantially linear conductive formation of Mobius ring effect. Practical active means achieving signal top-up or regeneration can be as cross-coupled bidirectional amplifiers between such double-looped conductive formations, say using N-channel and P-channel mosfet transistor formations as for typical CMOS VLSI chips. Practical dielectric includes silicon dioxide, e.g. field oxide or inter-metal dielectrics, but substrate dielectrics are usable when of semi-insulating or SOI (semiconductor-on-insulator) nature.
Rotary travelling wave clocking can be provided well into the plus- and plural-GHz frequency ranges even using current CMOS fabrication technology. The popular synchronous paradigm can be maintained, with such high frequencies available all over the chip areas by readily extendable plural frequency locked loops. There is no need for conventional external quartz crystal signal source nor for internal phase-lock loop (PLL) multiplication or other control. Also, the termination and reflection problems of conventional H-tree signal distribution do not apply; and there are predictable phases/phase relationships at all points (coherency), so clear practicality for moving away from the single-phase synchronous paradigm and its very high power spikes.